qtVlm is a navigation software designed for sailing boats. It is also a free weather grib viewer that accepts all kinds of gribs. It can read and display maps in various formats, such as Vector charts (S57), Raster Charts (kaps, geotiff, etc) and mbtiles charts.
It includes an AIS module and an Instruments Module, that can retrieve data from various NMEA sources, or from internal GPS. It can also send performance data (VMG, target speed, etc) to a navigation system.
qVlm is able to calculate the best course using Routes and Weather Routings modules. Many options are available, like multi-routing to find the best departure date-time according to various parameters, routing on a pathway, or taking in account segments with engine for instance. qtVlm can acquire position and NMEA information via various sources (internal GPS, tcp, udp or gpsd), and can display many navigation instruments and performance data.
A Start Line mode can be activated, which will calculate times and distances to line and show a safe zone, and also manages a chronometer.
qtVlm can also be used In Simulation Mode. In this mode qtVlm will use wind and currents data from grib to simulate navigation. All instruments will be usable, and real live AIS targets are received from Internet. Beware not to collide with a real fishing boat or another qtVlm boat.
There is also a pure Virtual Racing Mode based on VLM online races.
Vector charts (S57) and Geo-referenced marine maps (kap, geotiff, etc.), and mbtiles charts can be installed. qtVlm can also display maps from various Tiles Servers.
Several grib files can be loaded at the same time, in order to be able to route using various parameters (winds, currents and waves for instance). Weather faxes images can also be loaded on top of gribs.
Route and Weather Routing modules, navigation instruments, S57, mbtiles and Raster modules, AIS module, Iridium module, Start Line mode and Great Circle gribs management are available only with the full version, through in-app purchase.